Abstract: A compressor includes a motor driven by a controller and having a rotor and a stator, a compressing unit driven by the motor in a hermetic container in which refrigerant is filled. Driving the motor at a low rpm, the controller practices a feedback control which determines a timing of turning on/off switching elements based on a signal detecting a position of the rotor, and when the motor is driven at a high rpm, the controller practices an open-loop control which outputs a given frequency and drives the motor synchronizing with the given frequency. This structure achieves a compressor working with a fewer noises in PWM driving.

Abstract: A compressor includes a motor driven by a controller and having a rotor and a stator, a compressing unit driven by the motor in a hermetic container in which refrigerant is filled. Driving the motor at a low rpm, the controller practices a feedback control which determines a timing of turning on/off switching elements based on a signal detecting a position of the rotor, and when the motor is driven at a high rpm, the controller practices an open-loop control which outputs a given frequency and drives the motor synchronizing with the given frequency. This structure achieves a compressor working with a fewer noises in PWM driving.

Abstract: A porous filter having a pore size of no more than 80 .mu.m is provided in a refrigerant flow passage of a refrigeration system. The filter may be provided in a drier provided in the refrigerant flow passage or in a separate filter casing provided in the refrigerant flow passage. Alternatively, the filter may be provided in the refrigerant flow passage within a sealed casing of a refrigerant compressor which is incorporated in the refrigeration system. The filter is formed of a molded solid material constituted by alumina, silica gel, calcium sulfide and aluminosilicate.

Abstract: A porous filter having a pore size of no more than 80 .mu.m is provided in a refrigerant flow passage of a refrigeration system. The filter may be provided in a drier provided in the refrigerant flow passage or in a separate filter casing provided in the refrigerant flow passage. Alternatively, the filter may be provided in the refrigerant flow passage within a sealed casing of a refrigerant compressor which is incorporated in the refrigeration system.

Abstract: A hermetic compressor system includes a compressor and an electric drive resiliently supported in a closed housing. A metallic cylinder head is secured to the compressor and defines an insertion hole. The cylinder head has a suction chamber, which communicates with the insertion hole, and a discharge chamber integrally formed with and adjacent to the suction chamber. A suction muffler made of a synthetic resin or equivalent material of low thermal conductivity has a communicating duct extending through the insertion hole and partially disposed within the suction chamber. An opening is formed in the end of the communicating duct disposed within the suction chamber in a position facing a suction port leading a refrigerant gas into the compressor.